This application claims the priority of German Patent Application No. 100 33 796.1 filed Jul. 12, 2000, which is incorporated herein by reference.
The invention relates to a method for producing stand-up blister packages, in which method blister domes are shaped from a film sheet of thermoplastic plastic, separated from the film sheet, transferred into circulating, cyclically-moved sealing pallets, and filled and sealed with a carrier part through large-surface heating of the blister edges. The invention additionally relates to an apparatus for executing the method. The stand-up blister packages produced with the method have a high market appeal, because the consumer can easily read and identify the imprint on the carrier part when the. stand-up blister packages are arranged appropriately in store shelves.
A method of the above described type and an apparatus for generally carrying out that method are described in German laid open application DE 37 22 214 A 1. The blister packages produced with the method and apparatus have a blister edge that extends around the entire perimeter and protrudes over the entire contour of the blister dome, and prevents the packages from being displayed in an eye-catching, compact manner, namely, being stood up on a side wall of the blister dome.
U.S. Pat. No. 4,901,858 discloses a stand-up blister package in which the four blister edges are sealed with a carrier part. The provision of an undercut on one side of the blister dome, the undercut being approximately as wide as the blister edge, lends the package the stability required for standing. This undercut hinders the shaping of the blister dome, because it necessitates horizontal movements of the tool parts. Sealing the blister edge in the region of the undercut in the sealing station of an automatic blister-package machine also requires complicated tools with horizontally-moving parts, because the heated sealing electrode requires a countersurface for sealing. This countersurface must, however, be moved away laterally before it is moved downward. Because the blister dome must often be adapted precisely to the item to be packaged, a deviation in forming the undercut is unacceptable as a rule. The item would be too loosely packaged.
U.S. Pat. No. 3,093,244 proposes sealing all four blister edges of the blister dome with the carrier part and folding one of the sealed edges by about 90xc2x0. These stand-up blister packages lack stability, because the folded sealed edge is not secured. The edge therefore bends back to varying degrees, so the stand-up blister packages appear crooked, which has a negative visual effect. If the folded sealed edge were to be secured with suitable measures, the stand-up blister packages would be very bulky and difficult to stack, and would require considerable space for shipping from the packaging site to the retailer.
It is the object of the invention to execute the method to produce blister packages in which a blister edge only protrudes on three sides of the blister dome. On the fourth side, the blister edge is intended to be brought into a fixed position, so the blister package can stand directly on the side wall of the blister dome on this side. It should not be necessary to create an undercut in the blister dome. The blister packages are supposed to be packed compactly.
The above object generally is achieved according to a first aspect of the invention by a method for producing stand-up blister packages, in which blister domes with blister edges are shaped from a film sheet of thermoplastic plastic, separated from the film sheet, transferred into circulating, cyclically-moved sealing pallets, filled with an item and sealed with a carrier part through the large-surface heating of the blister edges, with the method including the following method steps:
sealing one of the blister edges with the carrier part in a transverse-sealing station;
cooling the one blister edge and the carrier part to form a stand-up blister package pre-form;
linearly heating the transition region of the one blister edge between the blister dome and the carrier part in a heating station to form a narrow, heated fold line;
folding the carrier part and the one blister edge connected thereto by 180xc2x0 along the heated fold line; and,
sealing the remaining blister edges with the carrier part to form the sealed stand-up blister package.
The above object generally is achieved according to a second aspect of the invention by an apparatus for producing stand-up blister packages according to the method of the invention including a shaping portion or section for providing shaped blister domes having blister edges; and a sealing portion or section with at least one circulating pallet belt having pallets with openings for receiving the blister domes and carrier portions on a surface of the pallets such that one blister edge overlaps a portion of a respective associated carrier, in the region of the at least one circulating pallet belt, a filling station, a transverse-sealing station for sealing the one blister edge with the carrier part, a folding station for folding the carrier part by 180xc2x0, a sealing station for sealing the other blister edges with the carrier part, and a heating station that is disposed between the transverse-sealing station and the folding station, with the heating station having a heated heating strip for warming a linear region of the blister dome in order to create a heated fold line. Advantageous modifications of the invention are disclosed and described.
The method is described in detail by use of schematic drawings of the apparatus for executing the method.